$-\dfrac{9}{8} - \dfrac{5}{12} = {?}$
Explanation: $ = - {\dfrac{9 \times 3}{8 \times 3}} - {\dfrac{5 \times 2}{12 \times 2}} $ $ = - {\dfrac{27}{24}} - {\dfrac{10}{24}} $ $ = - \dfrac{{27} - {10}}{24} $ $ = -\dfrac{37}{24}$